A photo-voltaic solar array is a means for converting solar radiation into electricity, which is well known in the art. A solar array typically consists of a collection of solar cells integrated with a structural support system, an environmental protection system, and an electrical energy distribution system. In some instances there are additional sub-systems such as concentrating optics and pointing systems. The systems are used in terrestrial applications and in space applications. A common problem area in using solar arrays is the reliability of the connection between the electrical energy distribution system and the solar cells. Exemplary prior art patents directed to solar cells or arrays include U.S. Pat. Nos. 4,296,270; 4,350,836; 4,685,608; 6,093,884; and 6,870,087; the contents of each of which are expressly incorporated herein by reference.
The current state of the art is to bond solar cells to their structural support using flexible adhesive, such as room-temperature vulcanizing (RTV) adhesive, and weld a thin foil conductor to the connector pads on the solar cells. An exemplary prior patent that discloses bonding between solar cells is U.S. Pat. No. 5,919,316 to Bogorad, et al., the contents of which are expressly incorporated herein by reference.
Solar cells are thin and brittle polycrystalline semi-conductor structures, similar in structural characteristics to silicon computer chips. The attachment of the conductive foil or wire to the cells involves the joining of dissimilar materials, usually by welding or soldering, which can cause weakened areas. Cyclic stresses due to periodic thermal changes can and often result in fatigue crack propagation in the joint that can ultimately lead to joint failure. When an electrical connection to the solar cell is broken, no energy flows from that cell and if that cell is in series with other cells, an entire string of cells can be out of service, thus reducing the overall system efficiency.